C# Access base class variables/functions from abstract class

Question

Maybe its not possible or i am mixing something up, but its breaking my head.

Let's say, we got an abstract class A and a class B based of A. Is it possible for A to access variables/functions from B?

Example:

 abstract class A
 {
    public bool activeA = false;

    public bool getState()
    {
        return test; // The variable from class B
    }
 }

 class B : A
 {
    public bool test = true;

    public void isActive()
    {
         return base.getState(); // So this should return true because getState() should access the variable test^^
    }

 }

Answer 1

No, this is not possible. A doesn't know anything about B or potentially C..Z.

If test would be on A, then both A and B could access it. Or you could create an interface that's implemented by B and that A knows about and pass B as a parameter to A.

This could look like this:

interface IB
{
    bool Test { get; }
}

abstract class A
{
   public bool activeA = false;

   public bool getState(IB arg)
   {
       return arg.Test;
   }
}

class B : A, IB
{
   public bool Test => true;

   public bool isActive()
   {
         return base.getState(this); 
    }
 }